This invention relates to a cutting device for agricultural harvesting machines such as, for instance, self-loading forage boxes or baling presses for harvesting agricultural stalk or leaf products such as grass or hay. Numerous versions of such cutting devices are known in the art. Essentially, they comprise a conveying mechanism driven in rotating fashion around a horizontal axis and equipped with conveying prongs, which works in conjunction with cutting blades protruding into a conveying channel to cut the stalk or leaf product taken up by a pick-up mechanism and to conduct it to a subsequently positioned loading chamber. Especially in baling presses for the production of round or cube-shaped crop bales, the mounting space available for installing such cutting devices is very limited.
German patent DE 31 41 414 A1 discloses a cutting device for a self-loading forage box, in which each knife blade is held in its cutting position by means of a spring-elastic blade lever, allowing it to yield automatically to a stone or other foreign object. The blade levers are mounted approximately in the middle to a fixed shaft, and the segment turned towards the blade, to which a blade roll is mounted, locks into a recess in the back of the blade, and the other segment, equipped with cam plates, locks into the control shaft positioned subsequently to the blade levers. The cam plates, one of which being assigned to each blade lever and therefore to each blade, are mounted to the control shaft in staggered fashion in such a way that either all, a certain number or none of the blade levers lock into a cam plate for setting the cutting length of the cutting device. This cutting device exhibits the disadvantage, first of all, that the installation of the blade levers and the subsequently positioned control shaft consumes considerable mounting space, adversely affecting the ground clearance of the agricultural harvesting machine. Secondly, such great force is required to activate the control shaft and therefore to set the cutting length that it is not possible for an operator to turn the control shaft by direct manual action. Instead, costly transmission gears or similar drive mechanisms are required.
Older German patent DE 32 13 199 C2 describes a self-loading forage box with a cutting device in which the cutting blades protruding into the conveying channel are held in the cutting position by means of support claws mounted to a control shaft in varying numbers in single rows running parallel to the axis. Supporting edges on the backs of the cutting blades lock into the support claws of the control shaft, forming an acute pressure angle, so that, whenever an excessive load is brought to bear upon one or more blades, the support claws move out of lock with the supporting edges of the cutting knives as the control shaft rotates away from the effect of the overload, thereby allowing the cutting blades to rotate out of the cutting position into a non-cutting position. A disadvantage of this cutting device consists in the fact that all activated cutting blades are allowed to rotate out of the cutting position whenever a stone or similar foreign object is encountered. Thus, it is not possible in this case either to protect individual cutting blades from overload and damage.
Therefore, an objective of the invention is to provide a cutting device for agricultural harvesting machines of the type mentioned above that would assure reliable protection of each individual cutting blade in a compact design requiring little installation space, is easy and inexpensive to produce, and for which an operator can set the cutting length with little expenditure of force.
In a cutting device for agricultural harvesting machines, such as, for instance, self-loading forage boxes or baling presses, the application of the invention-specific features assures reliable protection of each individual cutting blade, while the required installation room is kept to a minimum and therefore does not compromise the ground clearance even of baling presses and especially of baling presses for producing cube-shaped crop bales. This objective is accomplished by means of a support and control member assigned to each cutting blade, which, when set in one control position, provides elastic support for each individual cutting blade in a cutting position, and which, when set in another control position, allows the corresponding cutting blade to rotate out of its cutting position into a non-cutting position.
According to the invention, this objective is accomplished in that the rotatable support and control members mounted to an axis running parallel to the axis of the conveying mechanism features at least two control positions providing elastic support of the corresponding cutting blade in the cutting position, and one control position allowing the corresponding cutting blade to rotate out of the cutting position into the non-cutting position. When the support and control members are completely rotated, therefore, a control position is set in which all cutting blades are elastically supported in the cutting position, while in two other control positions, only every second cutting blade is set in the cutting position and elastically supported therein.
According to a further aspect of the invention, an intermediate position can be set between each control position. The purpose of this intermediate position is to allow all cutting blades to rotate simultaneously out of the cutting position into a non-cutting position. Thus, a joint rotation of the support and control members is required to switch between the different control positions, and the angle of rotation traversed in each such switch is equal to the angular pitch of the support and control members and is derived from the number of control positions. With three control positions, therefore, the angular pitch would be 120 degrees. The intermediate position between two control positions is attainable by jointly rotating the support and control members around an angle of rotation, the size of which corresponds to half the angular pitch.
Under an advantageous execution form, support rolls are assigned to the support and control members and interact with a backwards-supporting edge of the cutting blades to provide elastic support for the cutting blades. The number of support rolls for each support and control member is at least one less than the number of possible control positions. Under a preferred form of the execution, three control positions are provided, so that in two control positions, a support roll interacts with the backwards supporting edge of a cutting blade, while in the third control position, the absence of a support roll allows the cutting blade to rotate into a non-cutting position. The support and control members so designed are positioned in such a way that adjacent support and control members are staggered with respect to each other by an angular pitch.
According to a further aspect of the invention, the support and control members are mounted in rotatable fashion to a control shaft which runs crosswise to the direction of travel and work, so that the area of rotation of a support and control member, starting for instance from a stop mechanism designed as a spring-type dowel pin, works in opposition to the direction of force of an energy accumulator, here for instance a torsion spring. By mounting the support and control members to the control shaft in rotatable fashion, it is possible to provide elastic support to the cutting blades in the cutting position. When the cutting blade encounters a stone or similar foreign object, for instance, in the conveyer channel, it can therefore automatically rotate back out of the cutting position into a non-cutting position, as the corresponding support and control member on the control shaft, interacting with the backwards supporting edge of the cutting blade, is rotated back in opposition to the direction of force of the energy accumulator. Supported by the force of the energy accumulator, the cutting blade returns to the cutting position once the foreign object has passed through.
According to the invention, the cutting length for the harvest product can be changed in that the entire control shaft with all its support and control members is rotated and locked in place in the corresponding angular pitch. This process can easily be performed manually by an operator by means of a setting key provided for such purpose, for instance.